1. Field of the Invention
The present invention relates to a detecting device. In particular, this invention relates to a detecting device that detects whether a cash drawer is opened or closed.
2. Description of the Related Art
In retail stores, usually electronic ways are used to manage the payment for goods, such as point of sales (POS) systems. FIG. 1 shows a typical point of sales system. The POS includes a control host 1, and a cash drawer 2. The control host 1 provides a lot of basic functions, such as inputting price, calculating the total payments for goods, printing the receipt, and displaying the payments for goods, etc. The control host 1 also controls the cash drawer 2 to be opened via an electronic way so that the cash can be put into the cash drawer 2 or take out from the cash drawer 2.
The functional block of the point of sales system in FIG. 1 is shown in FIG. 2. In FIG. 2, the control host 1 controls a display unit 13, an operation unit 15 and a printing unit 17 via a control unit 11. At the same time, the control unit 11 uses a pin GPOUT to drive the electromagnetic switch 23 to be enabled and uses a pin GPIN to detect whether the cash drawer 2 is opened or not. The cash drawer 2 includes a housing 21 having an electromagnetic switch 23, a micro switch 24, and a drawer 22 that can be opened or closed for storing the cash. In the drawer 22, there is an induction driving circuit 221 that can automatically open the drawer 22 from the housing 21 when the electromagnetic switch 23 is enabled. Between the control host 1 and the cash drawer 2, there is a connection wire 25 for transmitting the signals.
Therefore, when the control unit 11 outputs a low level signal to enable the electromagnetic switch 23 via the pin GPOUT so that the drawer 22 is automatically opened and the micro switch 24 is sort-circuit, the control unit 11 detects a low level signal from the pin GPIN and confirms that the cash drawer 2 is in an opened status. At this time, the control unit 11 displays the information of the cash drawer 2 being opened on the display unit 13. On the contrary, when the cash drawer 2 is in the closed status (this means that the drawer 22 is closed in the housing 21), the micro switch 24 in the cash drawer 2 is open-circuit. Therefore, the control unit 11 detects a high level signal from the pin GPIN and confirms that the cash drawer 2 is in the closed status. Similarly, the control unit 11 displays the information of the cash drawer 2 being closed on the display unit 13.
However, when the cash drawer 2 is stolen or moved, the signal connection between the cash drawer 2 and the control host 1 is interrupted. At this time, the control unit 11 still detects a high level signal from the pin GPIN, and confirms that the cash drawer 2 is in the normal closed status. Therefore, the point of sales system of the prior art cannot show that status of the cash drawer 2 being stolen or moved. It has a cash-loss risk for the owner of the store.